Switched voice networks are generally of the time-division multiplex (TDM) type. TDM systems operate using switches and frames defined in time. In TDM systems, information is transmitted in frames. In-band signaling in a TDM system is inside each of the frames and is treated as a payload. A system utility takes a signaling part of the payload out of the frame and uses the information for billing purposes. This is also true for out-of-band signalling in the TDM system. A system utility recognizes the signal characteristics along with an associated payload and uses the information for billing purposes as well.
In private line exchanges customers can pay a flat rate regardless of usage. Collecting data does not occur since a bill is generated on a monthly basis, for example, and is the same every month. This type of billing system is used strictly for data transfer and not voice systems such as telephone or facsimile systems.
In telephone systems, for example, information for billing purposes is extracted by employing in-band signaling inside frames or out-of-band signaling. As noted above, the TDM system handles the in-band signaling as part of the payload or the out-of-band signalling and the associated payload. A system utility continuously extracts the signaling (dialing) part of the payload (and at the end of the day (midnight) produces an Automatic Message Accounting (AMA) record for calls spanning multiple days). That is, all network signalling is collected and sent to an appropriate billing system in the form of an AMA record. AMA is a standard billing format that directs what information is needed, where it is to go and or what to record for billing purposes. This precludes others such as hackers from accessing the information. All the billing pieces, such as time, length of call, party doing the calling, party being billed, billing company, type of service, etc., are collected and used to generate a bill. Because TDM systems operate on a time basis, billing occurs, along with other functions, at a predetermined time.
Asynchronous transfer mode (ATM) systems for transferring information are becoming more popular. Information in an ATM system is transmitted in cells rather than in frames as in a TDM system. Thus, ATM systems are flexible in terms of not having constraints as to the type of service being carried (voice, data, video, etc.).
There are no current standards on how to collect billing data from an ATM system. Standards exist only with respect to what data should be included in the AMA system. The current state of ATM technology has standards bodies working to study and approve standards in the areas of signaling, cell transfer, and accounting record format. However, using ATM in a switched voice and data network has not been achieved. Particularly, extracting billing (or other information) from a switched voice or data network using ATM has not been accomplished.